The uncle of an Irishman who was stabbed to death by one of the youngest children ever to plead guilty to murder said he is ‘not happy’ with the sentence handed down to the 13-year-old boy.

The boy, who cannot be named for legal reasons, pleaded guilty to the stabbing 53-year-old Christopher (Jack) Barry twice in the chest outside his home in Edmonton, north London, on December 14 last year.

He was locked up for a minimum of 11 years for the killing, but the victim's uncle Noel Barry, who raised Jack as a child, said Jack and his partner ‘have been handed a life sentence’.

“I’m not happy with the sentence at all,” Noel Barry said.

“The sentence does not reflect the seriousness of the crime.

“[The boy] left home with a knife and he showed his intention to use it, therefore the act was premeditated. I wouldn’t say Jack was the intended victim, he was in the wrong place at the wrong time.

Noel described Jack as a ‘very honourable, modest and dependable person’.

“He stood by his principles, this was proven at the scene of his death,” Noel continued.

“I don’t know if his partner [Sabrina Finn] will ever get over it, she’ll have recurring nightmares for the rest of her life.”

Noel, who raised Jack from the age of eight, said he became ‘more of a brother’ to him as he grew up.

He said people may make excuses for a young child but he believes a thirteen-year-old knows the difference between right and wrong.

“People make a lot of ‘he’s only a child’ but children now are very advanced,” he continued.

“I have a grandson and he’s 12 and he could take part in an adults’ conversation no problem. He’s very advanced now.

“A 13-year-old now is the equivalent of a 19-year-old in my time. They know right from wrong.

“As I understand English law, from the age of 10 for a crime such as this you can get an adult sentence –I can’t understand why he didn’t get life imprisonment.”

The court heard on Friday the boy had left a 13th birthday party with a group of friends, but returned to the wrong block of flats and came across Mr Barry, and his girlfriend Sabrina Finn.

When the victim refused to let his killer into the building, there was "pushing and shoving", the court heard.

The defendant produced a kitchen knife from his rucksack and demanded, "What you saying now? What you saying now?", before stabbing Mr Barry twice.

Mr Barry only noticed his wounds when he removed his jacket inside his flat and saw blood on his shirt. He then went into cardiac arrest and died.

The court heard that the boy had texted one friend telling him to inform anyone who asked that he had not been at the flat. He had told another he was going to prison. The boy was a member of a North London gang and had been excluded from a school after he was found carrying a knife.

The girlfriend of Mr Barry attended the sentencing.

Ms Finn said in a victim impact statement she would never be the same again following the horrific ordeal.

"Jack and I had four happy years together and this young man has taken that away from me. Jack saved my life last year when I had a serious medical condition which required emergency surgery. I could not do the same for him."

The boy's mother wept in court as Judge Stephen Kramer sentenced her son to be detained for at least 11 years.